Characterization of corrosion products formed on Ni 2.4 wt%–Cu 0.5 wt%–Cr 0.5 wt% weathering steel exposed in marine atmospheres

• Concentration of Cu (0.50%), Ni (2.38%) and Cr (0.49%) decreases corrosion rate.
• Ni tends to be distributed throughout the entire corrosion product layer.
• Cr tends to be concentrated in the inner part of the corrosion layer.
• Composition of WS does not influence the type of crystalline phases in the layers.
• Composition of WS and corrosion media influences the phase proportion in the layers.

Weathering steel manufactured with high concentrations of copper (0.5 wt%), chromium (0.5 wt%) and nickel (2.4 wt%) was studied with the aim of furthering knowledge on corrosion product characterization and performance in marine environments. Specimens exposed for two years in a rural atmosphere and two marine environments were characterized by optical microscopy, SEM/EDS, XRD and Raman spectroscopy and corrosion rates measured. The main phases found were ferrihydrite, maghemite and goethite in the inner corrosion layer, and lepidocrocite in the outer layer. Cu and Ni were homogeneously distributed while Cr tended to be concentrated in the inner layer.